Abstract

A non-blind, shift-invariant image processing technique that fuses multi-view three-dimensional image data sets into a single, high quality three-dimensional image is presented. It is effective for 1) improving the resolution and isotropy in images of transparent specimens, and 2) improving the uniformity of the image quality of partially opaque samples. This is demonstrated with fluorescent samples such as Drosophila melanogaster and Medaka embryos and pollen grains imaged by Selective Plane Illumination Microscopy (SPIM). The application of the algorithm to SPIM data yields high-resolution images of organ structure and gene expression, in some cases at a sub-cellular level, throughout specimens ranging from several microns up to a millimeter in size.

Figures (8)

SPIM schematic. The sample (S) is illuminated by a thin light sheet generated by passing a collimated laser beam through a cylindrical lens (CL). The region of the sample that is imaged onto the CCD camera by the objective (OL) and tube (TL) lenses is illuminated by the light sheet. The emission filter (EM) blocks scattered illumination light. The sample is scanned along the detection axis to create a 3D image stack. It can then be physically rotated to different orientations and re-scanned, generating sets of 3D stacks along different viewing angles. An immersion-medium-filled chamber (IC) encloses the specimen and reduces the negative effects of aberration-inducing interfaces.

Illustration of image distortions caused by anisotropic and spatially varying image quality, and the compensation thereof by fusing two images. a) The undistorted sample fluorophore distribution. Top row: Images distorted by reduced resolution horizontally (b) or vertically (c). d) Fusion of b) and c) shows improved resolution isotropy. Bottom row: Images distorted by absorption while detecting from the left (f) and from the right (g). h) Fusion of f) and g) shows improved spatial coverage of the sample. Arrows indicate the directions along which the light is detected.

Effects of the number of views used in the MVD-MAPGG fusion of paper mulberry pollen autofluorescence images. Top: slices perpendicular to SPIM rotation axis, for different numbers of fused images. Bottom: corresponding power spectra (plotted with a non-linear look-up table to emphasize the high-frequency components). The detection axes are indicated by the white arrows in a-d. Scale bar = 3 μm.

Medaka embryo, stage 32, nuclear label (green) and McF0001MGR-1G19bd1 in situ hybridization (red). Left: single-view images; right: 6-view MAPGG fusion. a,b) Maximum-value projections along orthogonal axes. The regions of expression of McF0001MGR-1G19bd1 in the tectum proliferative zone (TPZ), pineal gland (PG), and telencephalon (tel) are clearly visible. For comparison, the inset shows the traditional blue-labeled transmission image. c) Slice at the depth indicated by the dashed line in a). Internal structures such as the lens (L), pigmented epithelium (PE), ganglion cell layer (GCL), outer (ONL) and inner nuclear layers (INL), and the inner plexiform layer (IPL) of the retina are well-defined in the fusion. The illumination (ill), detection (det), and rotation (rot) axes are indicated for the single-view images. Scale bar = 200 μm. See also Movie 3, an animation of the MVD-MAPGG fusion showing maximum-value projections at the top and slices at the position indicated by the white line at the bottom. [Media 3]

Slices perpendicular to the anterior/posterior axis of the Drosophila melanogaster embryo shown in Fig. 5. Slices from a) a view showing the upper left portion of the embryo clearly; b) a view taken at 180° with respect to the orientation in a); c) a view taken at 45° with respect to a). d) Overlay of the slices in a-c). The views in a) and b) contain very little overlapping information, which would make them difficult to register in isolation. Scale bar = 100 μm. See also Movie 4, an animation of progressive construction of a running-mean registration target. Individual cross-sections are shown in the red channel, and the green channel shows the running mean registration target as each view is successively added. [Media 4]